Uncovering wall-shear stress dynamics from neural-network enhanced fluid flow measurements

Friction drag from a turbulent fluid moving past or inside an object plays a crucial role in domains as diverse as transportation, public utility infrastructure, energy technology, and human health. As a direct measure of the shear-induced friction forces, an accurate prediction of the wall-shear stress can contribute to sustainability, conservation of resources, and carbon neutrality in civil aviation as well as enhanced medical treatment of vascular diseases and cancer. Despite such importance for our modern society, we still lack adequate experimental methods to capture the instantaneous wall-shear stress dynamics. In this contribution, we present a holistic approach that derives velocity and wall-shear stress fields with impressive spatial and temporal resolution from flow measurements using a deep optical flow estimator with physical knowledge. The validity and physical correctness of the derived flow quantities is demonstrated with synthetic and real-world experimental data covering a range of relevant fluid flows

Deep Learning of Causal Structures in High Dimensions

Recent years have seen rapid progress at the intersection between causality and machine learning. Motivated by scientific applications involving high-dimensional data, in particular in biomedicine, we propose a deep neural architecture for learning causal relationships between variables from a combination of empirical data and prior causal knowledge. We combine convolutional and graph neural networks within a causal risk framework to provide a flexible and scalable approach. Empirical results include linear and nonlinear simulations (where the underlying causal structures are known and can be directly compared against), as well as a real biological example where the models are applied to high-dimensional molecular data and their output compared against entirely unseen validation experiments. These results demonstrate the feasibility of using deep learning approaches to learn causal networks in large-scale problems spanning thousands of variables

Real-time simulations of transmon systems with time-dependent Hamiltonian models

In this thesis we study aspects of Hamiltonian models which can affect the time evolution of transmon systems. We model the time evolution of various systems as a unitary real-time process by numerically solving the time-dependent Schr\"odinger equation (TDSE). We denote the corresponding computer models as non-ideal gate-based quantum computer (NIGQC) models since transmons are usually used as transmon qubits in superconducting prototype gate-based quantum computers (PGQCs).We first review the ideal gate-based quantum computer (IGQC) model and provide a distinction between the IGQC, PGQCs and the NIGQC models we consider in this thesis. Then, we derive the circuit Hamiltonians which generate the dynamics of fixed-frequency and flux-tunable transmons. Furthermore, we also provide clear and concise derivations of effective Hamiltonians for both types of transmons. We use the circuit and effective Hamiltonians we derived to define two many-particle Hamiltonians, namely a circuit and an associated effective Hamiltonian. The interactions between the different subsystems are modelled as dipole-dipole interactions. Next, we develop two product-formula algorithms which solve the TDSE for the Hamiltonians we defined. Afterwards, we use these algorithms to investigate how various frequently applied assumptions affect the time evolution of transmon systems modelled with the many-particle effective Hamiltonian when a control pulse is applied. Here we also compare the time evolutions generated by the effective and circuit Hamiltonian. We find that the assumptions we investigate can substantially affect the time evolution of the probability amplitudes we model. Next, we investigate how susceptible gate-error quantifiers are to assumptions which make up the NIGQC model. We find that the assumptions we consider clearly affect gate-error quantifiers like the diamond distance and the average infidelity.Comment: Dissertation, 203 pages, RWTH Aachen University, 2023. This dissertation includes and extends the results of arXiv:2201.02402 and arXiv:2211.1101

It Should Not Be Left to Chance: Ensuring a Good Education For All Our Children

This essay suggests that progressive education is equivalent to good education. Condliffe Lagemann poses the question: What do we need to do to ensure that good education becomes more universally available than it is today? The answer lies in developing a new science of education, one that better integrates research, practice, and policy, and does a better job of educating the public about education

The Impact of Agricultural Research in Tropical Africa: A Study of the Collaboration between the International and National Research Systems

CGIAR Study Paper on the problems and opportunities of international agricultural research in Sub Saharan Africa, and the impact of CGIAR Centers on African national agricultural research systems and on agricultural production and food security in Africa. Written by Hans E. Jahnke, Dieter Kirschke, and Johannes Lagermann and published as CGIAR Study Paper No. 21, part of the series comprising the CGIAR Impact Study of the 1980s

Strukturpolitik im Wandel: Wachstumsziel stärker gewichtet

Mit der neuen Förderperiode 2007 bis 2013 für die EU-Strukturfonds wird der Gestaltungsspielraum der Politik vergrößert. Welche Förderinstrumente der EU-Strukturpolitik gibt es und wie funktionieren sie? Wie sind die Wirkungen der strukturpolitischen Fördermaßnahmen zu beurteilen? Welche Anforderungen sind an „echte“ Cluster zu stellen? --

Evaluierung einer Wahrnehmungsschwelle von Kameratrackingfehlern beim Compositing realer und virtueller S3D-Videos

Dieses Paper präsentiert eine Studie zur Untersuchung der Akzeptanz von Kameratrackingfehlern in stereoskopischen Videosequenzen für den Einsatz in der Stereo-3D (S3D) Fernsehproduktion. Die klassische Betrachtungsweise von Fehlertoleranzen beim Kameratracking ist rein technisch motiviert. Im Zentrum dieser Studie wird deshalb aus zuschauerzentrierter Sicht die Fragestellung untersucht, ab welcher Ausprägung Trackingfehler in den sechs Freiheitsgraden der extrinsischen Orientierung der Kamera wahrgenommen, beziehungsweise als störend eingeschätzt werden. Dies geschieht unter Anwendung einer Variation der Methode der eben merklichen Unterschiede (Method of Limits). Die Auswertung zeigt, dass Unterschiede zwischen den einzelnen Parametern existieren und dass das subjektive Empfinden von Trackingfehlern weitaus toleranter ist als die harten rechnerischen Grenzen

A “guerra fiscal dos portos” e a Resolução 13/12 do Senado Federal: abrangência, efeitos e perspectivas.

RESUMO Esse artigo descreve o contexto em que foi gestada a Resolução 13/12 do Senado Federal com vigência a partir de 1º de janeiro de 2013 que objetiva enfrentar a guerra fiscal no ICMS entre os estados brasileiros no que concerne à importação de bens e mercadorias e aumentar a capacidade competitiva da produção nacional. Registra o esforço da administração tributária em implantar a medida de unificação em 4% da alíquota interestadual dos produtos importados de forma a permitir o controle dos fluxos comerciais de produtos industriais elaborados com insumos importados. E conclui a respeito da natureza da medida, classificando-a como uma solução parcial para a guerra fiscal dos portos, em consonância com a proposta de reforma tributária formulada pelo governo federal para o ICMS. Um dos efeitos imediatos foi a redistribuição da receita do ICMS relativa à importação entre os estados, em detrimento dos que utilizaram esse instrumento para atrair empreendimentos, principalmente de atacadistas. Mas o processo está em andamento e novas acomodações deverão ocorrer, criando a expectativa a respeito da mudança de fluxos comerciais e de relocalização de empresas. Palavras-chave: ICMS; guerra fiscal; Resolução 13/12 do Senado Federal TÍTULO EM INGLÊS “Harbors fiscal wars” and the 13/12 Senate Resolution: scope, effects and perspectives. ABSTRACT This article describes the context in which was conceived the Resolution 13/12 of the Brazilian Federal Senate, effective from January 1, 2013. That Resolution aimed to tackle the tax incentives competition between the Brazilian States involving the Tax on the Circulation of Commodities and Services (ICMS) with regard to the importation of goods and commodities, as well as to increase the competitive capacity of the national production. The paper registers the effort of tax administration authorities in deploying measures to unify in 4% the interstate rate on imported products, in order to allow the control of trade flows of industrial products made with imported raw materials. It concludes by analyzing the nature of that initiative, classifying it as a partial solution to the “ports fiscal war”, being in accordance with the tax reform proposal formulated by the Federal Government regarding the ICMS. One of its immediate effects was the redistribution of revenues of ICMS on imports between Member States, to the detriment of those who used this instrument to attract businesses, mainly of wholesalers. But the process is still underway, and new accommodations are likely to occur, creating the expectation of changes in trade patterns, as well as of business relocations. Key words: ICMS; tax competition; Resolution 13/12 of the Brazilian Federal Senate Artigo recebido em 23 set. 2013